The present invention relates to a front panel for a plasma display panel including powder components and a method for producing the same, and a plasma display panel.
Hitherto, as a display device for displaying high-definition television images in a large screen, expectations for a display device using a plasma display panel (hereinafter, referred to as a PDP) have been heightening. Hereinafter, a constitution of a PDP of a conventional example will be described.
The PDP of a conventional example is provided with a front panel and a rear panel.
The front panel includes a front glass substrate, a plurality of display electrodes formed into stripe form on one surface of the front glass substrate, a dielectric glass layer covering these display electrodes and a dielectric-protection layer covering the dielectric glass layer.
The rear panel includes a rear glass substrate, a plurality of address electrodes formed into stripe form on one surface of the rear glass substrate and a dielectric glass layer covering these address electrodes. A plurality of barrier ribs are formed into stripe form on the dielectric glass layer. These barrier ribs are parallel to the address electrodes and located so that the address electrode is positioned between adjacent barrier ribs as seen from a thickness direction of the rear panel. A red, green, or blue phosphor layer is applied in turn to a bottom in a groove formed by two sides of the adjacent barrier ribs with the dielectric glass layer.
The PDP has a hermetically-closed structure in which the front panel (the side on which the dielectric-protection layer is formed) and the rear panel (the side on which the barrier ribs are formed) are opposed to each other and the periphery of a space between these two panels is sealed with a sealing member. In hermetically-closed spaces formed by this hermetically-closed structure, a discharge gas such as neon (Ne) or xenon (Xe) is filled to form discharge spaces. When a predetermined voltage is applied between the display electrodes and the address electrodes, a gas discharge is generated in the discharge spaces. The PDP can display color images by exciting the phosphor layer according to the ultraviolet rays generated through the gas discharge to emit visible light.
On the other hand, it is known that by dispersing the powder components composed of dielectrics on the dielectric-protection layer of the front panel, the stability of initial electron emission emitted from the dielectric glass layer can be enhanced (improved), and a voltage required for maintaining a wall charge of the dielectric glass layer can be decreased.
The powder component can be produced by the following procedure, for example.
First, a primary particle having an average particle diameter of about 0.2 to 3.0 μm is produced by heat-treating magnesium hydroxide (MgOH).
Next, the produced primary particle is further fired (heat-treated) in order to promote a reaction of unreacted magnesium hydroxide (MgOH) and eliminate residual substances.
The particle diameter is ultimately adjusted to an average particle diameter of about 4.0 to 6.0 μm by this firing.
The powder component thus produced has a single crystal structure, and therefore the inside and the surface of the powder component become the condition where very small lattice defects typified by a point defect and a dislocation exist.
An average particle diameter of the powder components can be adjusted to a proper size.
When a large average particle diameter of the powder components is desired, this can be realized, for example, by further heat-treating the fired powder components. Thereby, the average particle diameter of the powder components can be set at a particle diameter of about several tens of micrometers to several hundreds of micrometers.
Further, when a small average particle diameter is desired, this can be realized, for example, by pulverizing the fired powder component with an Ultimizer. Thereby, the average particle diameter of the powder components can be adjusted to a level equal to that of the primary particle, or a size of about 0.2 to 3.0 μm.
Examples of PDPs of conventional examples, containing powder components, include a PDP disclosed in Patent Document 1 (i.e., Japanese Unexamined Patent Publication No. 2005-149743). In Patent Document 1, an alternating current (AC) PDP including a particle size distribution in which a grain size of the powder component is 5.0 μm or less is disclosed.